1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly relates to an image forming apparatus including a memory which stores image data supplied from a plurality of transmitters.
2. Description of the Related Art
Among image forming apparatuses of the above kind, an image forming apparatus has been known which enables a copy operation for copying an image read by an image reading unit constituted by a scanner or the like, and a print operation for printing image data supplied from an external unit such as a personal computer. Such an image forming apparatus includes a memory connected to transmitters of an image reading unit and an external unit for storing image data supplied from those transmitters, and an image forming unit which successively forms an image according to image data stored in the memory.
Particularly, in an image forming apparatus having a multi-job function, even if image formation is proceeding in the image forming unit according to image data for a group of original documents (job), registration of an image forming operation in which image data for another job is transmitted from an image reading unit or an external unit to be stored in a memory is possible.
However, there is a limitation in the number of jobs stored in the memory. Therefore, once image data for the limited number of jobs is stored in the memory, image data for a job transmitted from the image reading unit or the external unit is not accepted by the memory since the memory cannot store the data anymore, unless the number of jobs stored in the memory is reduced by forming an image in the image forming unit or the like.
In some cases, a user may desire to use the image forming apparatus for a job transmitted from a specific transmitter prior to using for any job transmitted from other transmitter.
When an image forming apparatus connected to a plurality of transmitters which transmit image data is integrally structured with an image reading unit, for example, a user often attends the image reading operation in the image reading unit. In this case, the user would desire to use the image forming apparatus for the image reading unit in preference to other units.
A problem occurring in such a case is that any job from an image reading unit which should be given a priority is not accepted in a conventional image forming apparatus if a transmitter other than that of the image reading unit transmits image data for a large amount of jobs even temporarily, since the large amount of jobs reach the limitation of storage of the memory.